URTI's Flashcards
What is the most significant method for transmission of the common cold?
Hands (droplet is less significant)
Describe the infectivity of the common cold
Viral shedding peaks on 3rd day, coinciding with peak symptoms. Low level shedding continues for 2 weeks.
What is the incubation period of the common cold?
24-72 hours
Name some viruses that cause the common cold
Rhinovirus, RSV, influenza, parainfluenza, adenovirus, enterovirus, coronavirus, human metapneumovirus
Briefly outline the pathogenesis of the common cold
- Virus deposited on nasal/conjunctival mucosa - attaches via host cell receptors
- Viral replication - host defence activated as cells are damaged
- Cytokine release (IL-8) attracts PMNs
- Increase in nasal secretions and slowed mucociliary clearance
Severity of symptoms of the common cold correlate with what?
IL-8 level
Rhinovirus infection results in the release of albumin and bradykinins, what is the outcome of this?
- Increased vascular permeability in nasal lamina propria
2. Bradykinins cause rhinitis, sore throat
What are the symptoms of the common cold in an infant?
Fever and and nasal discharge
What is the duration of the common cold?
10 days. Prolonged in smokers. Can last 2-3 weeks
What should be on your differential Dx (DDx) if you suspect the common cold?
- Allergic rhinitis
- Acute bacterial sinusitis
- Nasal foreign body
- Pertussis
- Structural abnormalities of the nose/sinuses
- Influenza
- Bacterial pharyngitis
What are some OTC recommendations for the common cold?
- Antipyretic/pain control
- Saline irrigation
- Steam inhalation
- Decongestants
The majority of the cases of pharyngitis are due to what?
Viruses
20-30% of sore throats in children and 5-15% in adults are attributed to this…
GAS (S. pyogenes)
Pharyngitis is unusual in children under the age of 3, T of F?
True, it is most common in school aged children.
What is the incubation period for GAS pharyngitis?
2-5 days
What is the infectivity of GAS pharyngitis?
- Highly communicable
2. Usually non-infectious within 24 hrs of antibiotic therapy
How is GAS pharyngitis spread?
- Person to person
2. Respiratory droplet
Viral pharyngitis is caused only by respiratory viruses, T or F?
False. Non-respiratory viruses may also be responsible.
Describe some of the virulence factors that S. pyogenes has.
- Capsule - hyaluronic acid (camouflage)
- M proteins - resist phagocytosis
- Invasins and exotoxins (hemolysins) - cause tissue damage
- Streptolysin O - cytotoxin (including myocardium)
If GAS pharyngitis is left untreated or is treated inappropriately, what risk does this pose?
3% risk of Rheumatic fever
What collection of clinical features may indicate a viral etiology for pharyngitis? (6)
- Conjunctivitis
- Cough
- Hoarseness
- Rhinorrhea
- Diarrhea
- Rash
What are the typical S/S of GAS pharyngitis? (4)
- Pharyngeal or tonsillar exudate
- Fever
- Tender/enlarged anterior cervical lymph nodes
- Absence of cough
When should you not test someone who presents with pharyngitis?
If the the S/S suggest a viral cause
What testing is available if you suspect bacterial pharyngitis?
- Throat culture
2. Rapid antigen detection test (RADT)
How should you manage viral pharyngitis?
- Symptomatic therapy: analgesic/antipyretic
2. NO ANTIBIOTICS
What is the Tx for GAS pharyngitis?
- Penicillin x 10 days
2. OR Clindamycin
List some benefits of antibiotic Tx for GAS pharyngitis
- Prevents complications (i.e. peritonsillar abscess, cervical lymphadenitis, rheumatic fever)
- Decreases transmission
- MINIMAL symptom improvement
In what age group is acute otitis media most prevalent?
Infants